Hi, I was using an older (11/23/04) version of limma package and it worked fine for my log ratio data. I just installed the latest version (2/24/05) but got this error message when I did: > lmFit(data) # data is just a matrix of log ratios. Error in sigToEnv(signature, fdef) : Trying to get slot "signature" from an object of a basic class ("NULL") with no slots Does anybody know why this is happening? Your help is appreciated. Yiwen He NIH [[alternative HTML version deleted]]

He, Yiwen (NIH/CIT) wrote: > Hi, I was using an older (11/23/04) version of limma package and it worked > fine for my log ratio data. I just installed the latest version (2/24/05) > but got this error message when I did: > > > > >>lmFit(data) # data is just a matrix of log ratios. > > > > > Error in sigToEnv(signature, fdef) : Trying to get slot "signature" from an > object of a basic class ("NULL") with no slots My bet is that data (bad variable name, btw; you are masking an existing R function) is not a matrix, but a data.frame. Try lmFit(as.matrix(data)) HTH, Jim -- James W. MacDonald Affymetrix and cDNA Microarray Core University of Michigan Cancer Center 1500 E. Medical Center Drive 7410 CCGC Ann Arbor MI 48109 734-647-5623